howlin' bearing.

obviously new to the forum here but i try to search before i say anything and i am very pleased with all the information on this website.

anyway my problem is i have a howling bearing somewhere on the rear of my '98 (4.0, ax-15, np231, 8.25 rear, d30 front. if that helps?) I did the wheel bearings and that didnt change a bit. one of my friends who thinks he is a mechanic told me its the pinion bearing. which i dont really want to do unless im changing gears and adding a locker, it just seems like a lot of work that im not confident with (setting up new gears that is.) i recently noticed that my trasnfer case is coated in some sort of lube. could this be the culprit? let me know your thoughts.

also read something about dodge truck np231's being able to mingle with the jeep. i love junkyard upgrades so any information (or a link to send me in the right direction) on this would be awesome! thanks everyone, keep up the amazing work.

I also have a 98 XJ with the ChryCo 8.25 rear axle. My Jeep has 142k on it and I had the same bearing noise you are describing at about 135k. My noise would present itself when letting off the throttle. I tried to live with it for awhile but it got louder and louder to the point I was concerned about taking it on long trips. I ended up having to replace the carrier bearings along with the pinion bearings. The axles and the ring and pinion gear were fine but replacing the carrier and pinion bearings ran me around $900. I have heard from a lot of people on this board that rear end noise is present in most 97 or later XJs and that you can run them a long time before they grenade. I guess it just comes down to how much it will bother you. I lasted a month before it drove me crazy. I enjoy driving it a lot more now knowing I'm not building towards disaster.

You can help pro long the bad bearings life and even help prevent a bad pinion bearing in the future by overfilling the rear end. Just fill it up till its full and with the bottle kinda block the fill hole and give it a good squeeze and put the plug on fast. What this does is allows more oil to reach the pinion bearing cause the oil level is higher. Also a lot of after market diff covers have the fill hole up higher then stock just for this reason.

Some will say this will cause you diff to leak but I disagree as long as your diff vent hose is not clogged it will be fine.